European held in a vault (4)
I believe the answer is:
pole
I believe this is a double definition.
'european' is the first definition.
(someone from Poland)
'a vault' is the second definition.
(thesaurus)
'held in' is the link.
(Other definitions for pole that I've seen before include "support" , "National from east" , "Chopin, for example" , "'Round rod, of wood say (4)'" , "Wooden rod" .)